Fluorinated compounds and process of producing same



Patented May 6, 1952 UNITED STATES PATENT OFF-ICE" FLUOR-INATED COMPOUNDS AND PROCESS OF PRGDUCINGSAME Paul E. Weimer, West Lafayette, Ind., assignor tog the United States of America aszrepresentedby the United States Atomic Energy Commission No Drawing. Application July 1'7, 1946, Serial No. 684,249

9 Claims. 1

This invention relates to highly fluorinated organic compounds and to their preparation. The invention is particularly concerned with perfiuoro compounds suitable for use as lubricants and to novel methods for making such compounds.

In the past it has been proposed to manufacture perfiuorinated compositions suitable for use as lubricants by the direct fiuorination of highboiling hydrocarbons such as petroleum derivatives of the lubricating oil type. While high-boiling petroleum derivatives can be fiuorinated by means of perfluorides, suchas silver difiuoride and cobalt trifluoride, to produce perfiuoro compound mixtures having valuable lubricant properties, the process results in the production of a large proportion of fluorinated by-products the production of which consumes a very substantial proportion of the valuable fluorinating agent.

An object of the present invention is to reduce the quantities of a fluorinating agent, such as cobalt trifluoride or silver difiuoride, necessary for the production of compositions of the perfiuorolubricant type. A further object of the invention is to manufacture perfluorolubricants from hydrocarbons not obtained from petroleum lubricant oils. A still further object of the invention is to produce perfluorinated compounds suit able for use as lubricants from aromatic hydrocarbon derivatives. Further objects will appear from the following description of the invention and detailed examples of its application.

In accordance with the present invention a polyalkylcondensation product of an alkene or chloralkane containing from 2 to 4 carbon atoms with a di-nuclear aromatic hydrocarbon is fluorinated to produce fiuorinated compounds containing at least 74% but less than 76% fluorine. The products of the novel process are highly stable perfluorinated compounds or mixtures of such compounds boiling in the range TOO-250 C. at millimeters of mercury.

Since the condensation products derived from dinuclear aromatic hydrocarbons with alkenes or chloralkanes contain about twelve less hydrogen atoms per molecule than naphthenes containing the same numer of carbon atoms in the molecule, the proportion of fiuorinating agent necessary to effect perfluorination is correspondingly reduced. This reduction in the quantity of fluorinating agent necessary also reduces the quantity of heat generated'in fluorinating each molecule and consequently renders the fluorination process susceptible of easier control than fiuorination of the materials of higher hydrogen content. .Thehydrocarbons.fromwhich theperfluorinated compounds of the inventionmay-beproduced may be obtained by condensing naphthaleneor diphenyl with ethylene, propylene, a normal butylene, or isobutylene employing a condensing agent such as aluminum chloride, ferric chloride, or zinc chloride. The same prod-ucts maybe ob tained by employing ethyl chloride instead of ethylene, propyl chloride and isopropyl chloride in place of propylene, etc. Such condensation products boiling from as low as about C. at 4 millimeters of mercuryto as high as about 250 Cat 2 millimeters of mercury have been employed to produce perfiuorinated compositions having valuable lubricant properties. The particular condensation product or mixture of condensation products desirable for any application may be selected in accordance with the properties desired in the final product. Thus condensation products of very narrow boiling range may be employed to produce perfluorinated compositions containing relatively few components. On the other hand where lubricant properties are the desideratum, the boiling range of the condensation products employed may be quite broad. It isusually preferable'to select a definite distillate fraction for further fluorination in order to eliminate from the initial hydrocarbon material to be fiuorinated those compounds which do not yield perfluorinated materials of the particulartype desired in any given instance. In this waythe fiuorinating agent can be employed with a maximum'degree of efiectiveness.

The fluorination processof the invention may be carried out by means of silver difluoride or cobalt trifluorideat temperatures of 200 C. to 400 C. .The fluorination may be carried out in a single step or in a series of steps. Better yields of desired perfiuorinated compounds are normally obtained by conducting the process in a series of steps rather than by attempting to effect the entire fluorination in one step employinga single body of fiuorinating agents.

Thefollowin'g examples further illustrate the nature of the invention. In the examples quantities are expressed in terms ofweight, unless otherwise indicated.

One hundred parts'of naphthalene and 1.0 parts of anhydrous aluminum chloride were placed in a nickel-lined rocking autoclave. Gaseous ethylene was then introduced into the autoclave until the pressure reached 1050 pounds per'square inch. The charged autoclave was heatedin an hour and a halftto 0.; at this temperature :the

raised to about 200 C. and the pressure increased during this period to about 2300 pounds per square inch. The temperature was further raised over an additional period of about three hours to a maximum of 268 C. During this period the pressure gradually diminished to 400 pounds per square inch. The autoclave was then cooled and the liquid contents washed with water to remove aluminium chloride. The resulting mixture was extracted with benzene and the benzene solution was dried by means of anhydrous calcium sulfate. The dried product was then distilled at an absolute pressure between 3 and 4 millimeters of mercury. Fifteen parts by weight distilled between 115 and 162 C.; one hundred thirty-five parts distilled between 162 and 230 C.; fifty-four parts remained as distillation residue.

Vapor of the 162-230 fraction was passed over silver difluoride in two reactors in series, the first reactor being maintainedat a temperature between about 285 C. and 295 C. and the second reactor at a temperature between about 300 C. and 330 C. The pressure on the system during the fiuorination process was maintained at about 50 millimeters of mercury. The product was a viscous, colorless liquid boiling between 110 C. and 160 C. at millimeters of mercury absolute pressure, stable to potassium permanganate, and

containing 74.6% of organic fluorine.

Example 2 One hundred and fifteen grams of biphenyl and 10 grams of anhydrous aluminum chloride were charged into an 800 milliliter rocking autoclave. Sufficient ethylene was then introduced to give a pressure of 950 pounds per square inch at a temperature of 30 C. In a period of about a half hour the temperature was raised to 110 C. and during this period the pressure increased slightly to 1000 pounds per square inch. During the next half hour the temperature was raised about 5 C. and in this period the pressure decreased to about 125 pounds per square inch. The autoclave was then allowed to cool and additional ethylene was introduced to provide a pressure of 925 pounds per square inch at 25 C. The charge was heated as in Example 1 until the pressure had dropped to about 250 pounds per square inch. The pressure attained a maximum of about 1300 pounds per square inch after two hours of heating and gradually diminished in the next three hours to the final pressure. The autoclave was cooled and the viscous liquid product was removed and mixed with water to dissolve the aluminum chloride. The resulting emulsion was extracted with benzene and the benzene solution was dried with anhydrous calcium-sulfate. The dried product, after topping to remove benzene solvent, was distilled at between 2 and 3 millimeters of mercury absolute pressure. Twentyfive grams of distillate was obtained at 101- 185 C., forty-three grams at 185-2l0 C. and ninety-nine grams at 210-240 C.; nineteen grams of residue remained. V

A portion of the product distilling at 210-240 C. at 2-3 millimeters of mercury absolute pressure was passed over silver difiuoride maintained at temperatures between 300 and 360 C. The reaction vapors were condensed. The product most of which distilled between 140 and 210 C. at 10 millimeters of mercury absolute pressure was a viscous, colorless liquid stable to potassium permanganate and containing 74.3% organic fluorine.

variations and modifications of the invention and that the preceding examples are illustrations only and in no wise to be construed as limitations upon the invention, the scope of which is defined in the appended claims wherein I claim:

1. A perfluorinated oil containing at least 74% and less than 76% organic fluorine and boiling Within the range -250 C. at 10 millimeters of mercury absolute pressure, obtained by fiuorinating a polyalkyl condensation product of a 2 to 4 carbon atom alkyl group with a dinuclear aromatic hydrocarbon.

2. A perfluorinated oil containing at least 74% and less than 76% of organic fluorine and boiling within the range 1l0-l60 C. at 10 millimeters of mercury absolute pressure obtained by fiuorinating a polyalkyl condensation product of ethylene wi th naphthalene.

3. A perfluorinated oil containing at least 74% and less than 70% of organic fluorine and boiling within the range -2l0 C. at 10 millimeters of mercury obtained by fluorinating a polyalkyl condensation product of ethylene with biphenyl.

4. The method of making a perfluorinated oil suitable for use as a lubricant, which comprises subjecting to substitutive and additive fluorination a polyalkyl condensation product of a 2 to 4 carbon atom alkyl group with a dinuclear aromatic hydrocarbon, by reacting vapors of said condensation product with a metal polyfluoride selected from the group consisting of silver difluoride and cobalt trifluoride at temperatures of 200 C. to 400 C.

5. lhe method of making a perfluorinated oilsuitable for use as a lubricant, which comprises subjecting to substitutive and additive fiuorination a polyalkyl condensation product of "a2to 4 carbon atom alkyl group with ardinuclear aromatic hydrocarbon, said condensation. product boiling within the range -250 C. at 2-4 millimeters of mercury absolute pressure, by reacting vapors of said condensation product with a metal polyfluoride selected from the group consisting of silver difiuoride and cobalt trifiuoride at temperatures of 200 C. to 400 C.

6. The method of making a perfluorinated oil suitable for use as a lubricant, which comprises fluorinating to an organic fluorine content of at least 74% but less than 76%, a polyalkyl condensation product of ethylene with naphthalene, by reacting vapors of said condensationproduct with a metal polyfiuoride selected from the group consisting of silver difluoride and cobalt trifiuoride at temperatures of 200 C; to 400 C.

7. The method of making a perfluorinated oil suitable for use as a lubricant, which-comprises fluorinating to an organic fluorine content of at least 74% but less than 76%, a polyalkyl condensation product of ethylene with biphenyl by reacting vapors of said condensation product with a metal polyfiuoride selected from thejgroup consisting of silver difluorideand cobalt trifluoride at temperatures of 200 C. to 400 C. 1

8. The method of making, a perfluorinated oil suitable foruse as a lubricant, whichicomprlses It Will be understood that I intend to include fiuorinating to an organic fluorine content of at least 74% but less than 76%, a polyalkyl condensation product of ethylene with naphthalene, boiling within the range ISO-230 C. at 3-4 millimeters of mercury absolute pressure, by reacting vapors of said condensation product with silver difiuoride at temperatures of 200 C. to 400 C. 9. The method of making a perfluorinated oil suitable for use as a lubricant, which comprises fiuorinating to an organic fluorine content of at least 74% but less than 76%, a polyalkyl condensation product of ethylene with biphenyl, boiling within the range 210-240 C. at 2-3 millimeters of mercury absolute pressure, by reacting" vapors of said condensation product with silver difluoride at temperatures of 200 C. to 400 C.

PAUL E. WEIMER.

REFERENCES CITED The following references are of record in the file of this patent:

6 UNITED STATES PATENTS Number Name Date 2,013,035 Daudt et al Sept. 3, 1935 H 2,404,374 Harmon July 23, 1946 2,411,159 I-Ianford Nov, 19, 1946 2,488,216 McBee et a1 Nov. 15, 1949 FOREIGN PATENTS Number Country Date 10 429,591 Great Britain May 28, 1935 OTHER REFERENCES Bigelow et al., J. Am. Chem. 800., vol. 55, pp. 4614-20 (1933).

Rufl et al., Zeit. Anorg. Allgem. Chem, vol. 219, pp. 147-48 (1934).

Fukuhara et al., J. Am. Chem. 800., vol. 63, pp. 2792-95 (1941).

Henne et al., J. Am. Chem. Soc., vol. 67, pp. 1235-37 (Aug. 9, 1945). 

1. A PERFLUORINATED OIL CONTAINING AT LEAST 74% AND LESS THAN 76% ORGANIC FLUORINE AND BOILING WITHIN THE RANGE 100-250* C. AT 10 MILLIMETERS OF MERCURY ABSOLUTE PRESSURE, OBTAINED BY FLUORINATING A POLYALKYL CONDENSATION PRODUCT OF A 2 TO 4 CARBON ATOM ALKYL GROUP WITH A DINUCLEAR AROMATIC HYDROCARBON.
 4. THE METHOD OF MAKING A PERFLUORINATED OIL SUITABLE FOR USE AS A LUBRICANT, WHICH COMPRISES SUBJECTING TO SUBSTITUTIVE AND ADDITIVE FLUORINATION A POLYALKYL CONDENSATION PRODUCT OF A 2 TO 4 CARBON ATOM ALKYL GROUP WITH A DINUCLEAR AROMATIC HYDROCARBON, BY REACTING VAPORS OF SAID CONDENSATION PRODUCT WITH A METAL POLYFLUORIDE SELECTED FROM THE GROUP CONSISTING OF SILVER DIFLUORIDE AND COBALT TRIFLUORIDE AT TEMPERATURES OF 200* C. TO 400* C. 